How much of this is not true (long read)

Thanks Tom. I do appretiate your (and others) posts. Though some posts are over my head when it comes to technology or even how things are worded can bring additional questions. When it comes to Settings seems their is always a give and a take. Compromise may be Ok on an unfamiliar site...then tweak to sute. Agreed the Nox is one of the worlds flagships. Long live multi-frequency....love it.



Edited 1 time(s). Last edit at 11/17/2019 10:57PM by Arkansas.

Yes, very thankful for Tom's input into the Nox and for the insight as to squeezing the best out of it.

ghound Wrote:
-------------------------------------------------------
> Was this ever proven that Nexus had produced a det
> ector that went deeper in ground than in air?
>
> Quote from Nexus,
>
> I was one of the most fears supporters of the idea
> that VLF detectors can not detect deeper (or at le
> ast better) in the ground than they ever could in
> air. Our best ever results in some conditions were
> air to ground same measurements, but never better
> in the ground.
> The new Nexus Standard MP change that. The measure
> d average signal detection in ground with the MP i
> s 12-14% better than in air, BUT ONLY AFTER THE GR
> OUND BALANCE IS DONE.
>
> In absolute values VLF detectors will always be mo
> re sensitive in air than in ground, simply because
> their sensitivity in air can be boosted almost ind
> efinitely and for detection in ground that same se
> nsitivity will have to reduced dramatically for pr
> oper functionality.
>
> So if one chooses to compare the absolute values t
> hen the answer is no.
>
> But if one chooses the values in the real working
> environment then the answer is yes.

Here is the demonstration of what Nexus MP does in the ground.

Nexus Standard MP underground test

Please before anyone goes on - but in the real search blah, blah let me save you the trouble of guessing in the dark. This happens with the MP repeatedly in real search for most targets and in most conditions.

What does the quote (from ghound) above means?

The depth of any detector should never be considered from what the detector does in air tests, but only after ground balance is done and working adjustments for the given conditions are obtained, then and only then comparisons between in air sensitivity and in ground depth will have any meaning.
Then and only then different detectors can be actually compared.

Sheer in air sensitivity of any detector is non-sense as the ground is the limiting factor of all claims.
This is why the latest Nexus detector models are actually less sensitive in air than most other detectors especially the Nexus MP, but in the ground no other VLF will get ever close to the MP. This is especially true for highly mineralised conditions.

It would be great to see a H2H between the Tarsacci MDT 8000 and the Nexus MP on a mineralized ground and black sand.

Liked the video. Interesting test...… along with interesting methodology for test set-up.

I'd surmise, if Tom was accurately able to detect a clad dime in wet-sand at 12.5" and the same dime in the air at 11.5" (and detector freq did not change), then either 1) some unknown EMI lessened detector sensitivity (e.g., changing coil axis from horizontal (sweeping) to vertical (detector laying on the ground, sustained polarized EMI that decreases sensitivity) or 2) that particular soil mineral matrix aided depth by focusing the two-way magnetic field lines (e.g., elongated vertically orientated iron acted to channel field deeper or saturated soil minerals aligned to extend the field, etc.) or 3) detector sensitivity in the air was slightly diminished due to not having an adequate ground matrix to balance against, lowering detector performance.

The test result differences between regularly acquiring a dime at 12.5" in the air, 12.0" in dry soil, and 14.0" in the wet-salt environment make the causative factor most likely the soil matrix, especially being saturated. Typically EMF coupling to a target is inhibited by noise and repulsive secondary fields from conductive salt ions. Somehow, one must suppose, the salts distort the EMF to perhaps narrow the field pattern, where conductive salt ions act to effectively repel the field's normal horizontal expansion and herd/concentrate them deeper. I can envision this but not how the soil would naturally achieve such an arrangement on a regular basis?

-Johnnyanglo

I think that if a detector is getting less depth in Air than it is in Ground, you should be looking for reasons why the Air result is compromised. And as suggested, EMI differences are a prime candidate for this.
One test you can do, is fix the coil above the ground, at exactly the same height, place etc that the Ground test was performed. Then do the Air test, sweeping the coin etc above the coil. The ground isn't moving, so doesn't affect the detector's response - but it is quite likely to be lowering EMI, in my opinion/experience.

As an aside, it's worth pointing out that 'VLF' pinpointers detect further in Ground than in the air. This is due to them treating ground and coin as the same, there is no attempt at seperation/filtering the signals. So simply bringing the pointer close to the ground will bring it closer to the threshold of 'beeping'.



Edited 1 time(s). Last edit at 11/19/2019 10:32AM by Pimento.

[imgur.com]
Watching the Nexus test on the first coin, the sensitivity is set at it's lowest point, so I'm guessing it probably air tests much more than 40cm at full sensitivity, maybe another 30cm, so would it then still get deeper than it air tests at full power?

I thought I'd try similar with my Nox, so with a low sensitivity of 5, i can air test a 19mm milled silver at 10cm. When i put it in ground at 10cm i can still hit it at probably 11-12cm (personally i think its to vague as to say when you stop hearing the coin) so going by this theory a Nox can go deeper in ground than in air also lol



Edited 4 time(s). Last edit at 11/19/2019 09:49AM by ghound.

I use both the Nexus standard SE with the dual 9'' coil and the Nexus MP with 4 coils from the 8x6,10'',13'' DD coils and the 11'' Concentric,not the easiest machines to master especially the MP but after 3-4 years one has finally mastered both of them,never air test with them anyway as i cannot see the logic behind that test,but they are very very deep machines.Surisingly enough my favourite coils are the dual 9'' on the SE and what is a surprise is that i prefer the 8x6 coil the most on the MP,not only is the smaller DD coil exceptionally good for target separation but for its size is phenomenally deep for its size.

Are they deeper ?? if setup up right my reply would be after 3-4 years of use 'yes' would i use one/them as everyday machines my reply would be no,they are more for specialised use and that is exactly what i use them for,on clean open pasture sites or when are those ultra deep relics.My favourite out of both of these machines is the older Standard SE very very deep especially with that dual 9'' coil but its so much easier to setup and use and that is what makes it my favourite !! of course its just my personal opinion.

John & Pimento...… you trigger a thought (test) of mine...….. that I shall respond to..... on another thread ("On My Mind-Random Thoughts").

Junk and Disorderly Wrote:
-------------------------------------------------------
> I use both the Nexus standard SE with the dual 9''
> coil and the Nexus MP with 4 coils from the 8x6,10
> '',13'' DD coils and the 11'' Concentric,not the e
> asiest machines to master especially the MP but af
> ter 3-4 years one has finally mastered both of the
> m,never air test with them anyway as i cannot see
> the logic behind that test,but they are very very
> deep machines.Surisingly enough my favourite coils
> are the dual 9'' on the SE and what is a surprise
> is that i prefer the 8x6 coil the most on the MP,n
> ot only is the smaller DD coil exceptionally good
> for target separation but for its size is phenomen
> ally deep for its size.
>
> Are they deeper ?? if setup up right my reply woul
> d be after 3-4 years of use 'yes' would i use one/
> them as everyday machines my reply would be no,the
> y are more for specialised use and that is exactly
> what i use them for,on clean open pasture sites or
> when are those ultra deep relics.My favourite out
> of both of these machines is the older Standard SE
> very very deep especially with that dual 9'' coil
> but its so much easier to setup and use and that i
> s what makes it my favourite !! of course its just
> my personal opinion.

I find the exact opposite to you i can set up the MP much easier than the older Standard SE especially the ground balance but i agree that i would not use either as my day to day detector and just like you find they come into their own on old pasture.